Composition comprising cellulose ester and diisocyanate modified polyester amide



coMPosmoN COMPRISING cELLULosn ESTER p nnsocmmrn MODIFIED POLYESTER JohnH. Prichard, Springfield, N. J., assignor to Celanese Corporation ofAmerica, New York, N.Y., a corporation of Delaware No Drawing. FiledJuly 16,1958, Scr. No. 748,793".

13 Claims. c1; 260-16) been found to show poor resistance to staining,and particularly, staining due to contact with lipstick and type Writerribbon ink.

Thus, molded typewriter keys, telephone handsets and the like, preparedfrom cellulose propionate or cellulose acetate-butyrate are readilystained on contact with lipstick; the resultant stain being. irremovableeven upon washing with detergents; the stain beingespecially noticeableon molded keys in the lighter colors.

It has been found that the staining of such molded compositions may beattributed, at least in part, to the plasticizer content of thecomposition. While the degree of stain may vary with the specificplasticizer and the particular cellulose ester, it is noted that adecrease in the proportion of plasticizer used appears to increase theresistance of the molded product to staining.

However, a reduction in plasticizer content, leads' to an increase inmoisture absorption and a decreasein toughness and impact strength, aswell as a deterioration in other properties of the products molded fromcellulose esters having reduced proportions of plasticizer.

Accordingly,an object of this. invention is to provide an improvedplasticized cellulose ester molding composi-' tion which may beconvertedeasily into molded products such as typewriter keys, telephonehandsets and'the like, which have a high resistance to staining bylipstickjor ink from typewriter ribbons, yethaving good impactstrengthand toughness.

. Another object of this invention is to, provide improved moldingcompositions wherein the conventional monomeric plasticizers arereplaced in whole or in part by a cellulose acetate or celluloseacetate-butyrate is intimately mixed with a plasticizer in the form of adiisocyanate modified polycarboxylic acid ester amide.

In another aspect of the invention, the plasticizer for the celluloseester is made up of a major proportion of the diisocyanate-modifiedpolycarboxylic acid ester amide,

and a minor proportion of a 'monomeric plasticizer. When the celluloseester is the acetate, the preferred monomeric plasticizer is a phosphateester, such as dimethyl phosphate, diethyl phosphate or dimethoxy ethylite States Pat phosphate. When the cellulose is esterified with acids ofaverage chain length in excess of 2.0, the preferred monomericplasticizer is a carboxylic acid esterrhaving. a molecular weightbetween about 280 and about 420,-

such as dibutyl sebacate, dioctyl phthalate, butanediol dicaprylate ortriethylene glycol dicaprylate.

The diisocyanate modified polyester amide may be formed from thereaction product of a saturated dicarboxylic acid such as adipic,succinic, sebacic, azelaic or thelike dibasic acid, and a saturateddihydric alcohol.

cyanate such as hexamethylene diisocyanate, ethylene diisocyanate,trimethylene diisocyanate, m-phenylene diisocyanate, or cyclohexylenediisocyanate.

The polyester amide, prior to diisocyanate modification, preferably hasa molecular weight between 500 and 3,000 and instrinsic viscosities inthe range of 0.1

polyesteramide.

of ethylene glycol, adipic acid and monoethanolamine in molarproportions of about 8:10:3.

The reaction of the polyester amide with the diisocyanate effectsend-linkage of the primary" polymer and increases its molecular weightto above 5,000. Preferably between about 0.05 and about 0.10 mole ofdiiso;

vention and a description of the method of preparing such polymers maybe found in British Patent 553,733.

The resinous cellulose derivative is preferably an organic ester ofcellulose with one or more carboxylic' acids, such as cellulose acetate,cellulose propionate, cel-' lulose butyrate, cellulose acetatepropionate and cellu-' lose acetate-butyrate. Because of their toughnessand i dimensional stability, esters with aliphatic carboxylic' acidshaving an average chain length in excess of about 2.0 and particularlythose having an average chain length between about 2.5 and 3.4, areutilized in applications where they are vfar more likely to come intocontact with; staining materials and are the resinous cellulose deriva'-tives most preferred for the purposes of this invention. In accordancewith one aspect of this invention, theresin is preferably in particulateform, such as in the form of powder, grains,.fiakes or pellets. is inuniform admixturewith the resin, so that each pellet, forexample,comprises a uniform mixture of resin and plasticizer.

p the former to 17.5 parts of the latter, the mixture driedat 100-105"C. and compression molded into test discs.

Lipstick was applied to the discs which were then aged Thediisocyanate-modified, polyester amide is generally a material ofrubbery consistency and the admixture is accomplished on conventionalrubber working equipment, such as malaxating rolls.

Example Cellulose propionate was mixed-withtriethylene glycoldicaprylate in the proportions by weight of parts of.

for 24 hours at F. The discs were cooled to room temperature and thelipstick-was wiped off with a soft paper tissue. Considerable stain wasnoted on the discs.

The discs were then washed with warm}water contain ing a detergent,rinsed with distilled water and dried The discs still showedconsiderable stain. Upon making up similar molded discs, from cellulosepropionateconr W taining no plasticizer or very small amounts ofplasticizer P atented Feb. 7, 1961 It has between about 0.1 and about0.5 amino linkages for each carboxylic group. A typical polyester amide,for example, would be a condensation polymer The plasticizer 3 of themonomeric type (of the order of 7.5 parts of plasticizer per 100 partsof resin) and subjecting the same to lipstick, as outlined above,stainir xg was considerably reduced. However, the molded samples showedlow impact strength, reduced toughness, increased surface hardness andotherwise indicated an" insuflicient' content of plasticizer.

' Cellulose propionate amounting to 100 parts by weight was mixed with 5partsof butanediol dicaprylate and 20 parts of an isocyana'te-modifiedpolyester amide made by reacting 5 parts by weight of hexamethylenediisocyanate with 100 parts of the reaction product of adipic acid,ethylene glycol and ethanolamine in the proportion of 1.0:0.9:0.2. Testpieces, injection molded from such a composition had lipstick appliedthereto and removed by wiping and washing, as described above. It wasfound that the lipstick had left a very slight stain;

' Molding compositions made from other cellulose est'ers such as 100parts of cellulose acetate-butyrate and plasticized with from 15 to 25parts by weight of diisocyanate modified polyester amide, upon moldingby compression or injection, produced molded products showing littlestain after being subjected to lipstick or the ink from typewriterribbons. The polymeric plasticizer could be augmented with up to 7 partsby weight of monomeric plasticizers such as triethylene glycoldicaprylate, butanediol dicaprylate, dibutyl sebacate, dioctylphthalate, dioctyl adipate, and still produce a molded product havinggood resistance to staining. f,

'fLipsticks gener'aily contain as colorants, Drug and Cosmetic Dyes RedNo. 19, Red No. 21, Red No. 27 and Qra'nge No. 5, singly or incombinations thereof, carried in a vehicle of a waxy or fatty nature,including castor oil, polyethylene glycol, various natural and syntheticwaxes, and the like. While the residual stain due to contact of lipstickwith molded cellulose esters containing conventional monomericplasticizers will vary in degree, dependent on the particularcolorantand vehicle of the lipstick, it was found that such residualstain was materially reduced when the polymeric plasticizer of theinstant invention. alone or in combination with small proportions ofmonomeric plasticizer was compounded with the celluloseester to make upthe molding compositions of the instant invention. 1

; It is understood that the foregoing detailed description is givenbyway of illustration and that variations may be made therein withoutdeparting from the spirit of my invention. i

Having described my invention, what I desire to secure by Letters Patentis:

::;l. A composition comprising a resinous organic ester of .cellulosewith at least one lower aliphatic, monocarboxylic acid plasticized withfrom 15 to 25% based onlthelweight of said cellulose ester of aplasticizer comprising a diisocyanate modified polyester amide,saiddiisocyanate being selected from the group consisting ofhexamethylene diisocyanate. ethylene diisocyanate, trimethylenediisocyanate, m-phenylene diisocyanate and cyclohexylene diisocyanate,and-said polyester amide being a reaction product of asaturateddicarboxylic acid selected from the group consisting of adipic,succinic, sebacic and azelaic acids, a saturated dihydric alcoholselected from the group consisting of ethylene glycol, diethylene glycoland propylene glycol, and an amino compound selected from the groupconsisting of ethanolamine, 3-amino propanol, decamethylene diamine, and10-aminodecanol. I

-' 2. The composition of claim 1 wherein said carboxylic acid has anaverage chain length of at least 2.0.

,3. A composition as in claim 1 wherein 100 parts of esteris plasticizedwith 1,5 to 25 parts of said plasticizer. '4. The composition of claiml.wherein said diisocyanate modified. polyester amide isthereaction-product of "a polyester amide having a molecular weight between500 and 3000 and having from 0.1 to 0.5 amino linkages for eachcarboxylic group with from 0.05 to 0.10 mole of diisocyanate per dibasicacid residue in the polyester amide.

5. The composition of. claim 2 wherein said carboxylic acid has anaverage chain length between about 2.5 and prising adiisocyanate-modified polyester amide, said diisocyanate being selectedfrom the group consisting of. hexamethylene diisocyanate, ethylenediisocyanate, trimethylene diisocyanate, m-phenylene diisocyanate andcyclohexylene diisocyanate, and said polyester amide being a reactionproduct of a saturated dicarboxylic'acid selected from the groupconsisting of adipic, succinic, sebacic and azelaic acids, a saturateddihydric alcohol selected from the group consisting of ethylene glycol,diethylene glycol and propylene glycol, and an amino com pound selectedfrom the group. consisting of ethanolamine, 3-amino propanol,decamethylene diamine, and IO-aminodecanol.

7. A moldingcomposition comprising .a resinous lower aliphaticmonocarboxylic acid ester of cellulose in particulate form plasticizedwith a plasticizer comprising from 15 to 25%. based on the weight ofsaid cellulose ester of a diisocyanate-modified polyester amide and upto 7% based on the weight of said cellulose ester of a carboxylic acidester having a molecular weight between about 190 and about 420, saiddiisocyanate being selected from the group consisting of hexamethylenediisocyanate, ethylene diisocyanate, trimethylene diisocyanate,mphenylene diisocyanate and cyclohexylene diisocyanate, and saidpolyesteramide being a reaction product of a saturated dicarboxylic acidselected from the group consisting of adipic, succinic, sebacic andazelaic acids, a saturated dihydric alcohol selected from the groupconsisting of ethylene glycol, diethylene glycol and propylene glycol,and an amino compound selected from the group consisting ofethanolar'nine, 3-amino propanol, decamethylene diamine, andIO-aminodecanol. w

8. A molding composition as in claim 7 wherein said polyester amidecomprises the hexamethylene diisocyanate-modified reaction product ofadipic acid, ethylene glycol and ethanolamine. a

9. A molding composition for making molded products: resistant tostaining by lipstick comprising 100 parts of cellulose propionate, 15 to25 partsof a diisocyanate modified polyester amide and up to 7 parts ofa carboxylic acid ester selected from the group consisting of butanedioldicaprylate, triethyleneglycol dicaprylate. dibutylj sebacate, dioctyladipate and dioctyl phthalate, said-- diisocyanate being'selected'fromthe group consisting of" hexamethylene diisocyanate, ethylenediisocyanate; tr'imethylene diisocyanate, -m-phenylene diisocyanate andvcycloheXylene diisocyanate, and said polyester amide being a reactionproduct of a saturated dicarboxylic acid selected from the groupconsisting of adipic, succinic, sebacic and azelaic acids, a saturateddihydric alcohol selected from the group consisting of ethylene glycol,di-

saturated dicarboxylic acid selected from the group consisting ofadipic, succinic, sebacic and azelaic acids, a saturated dihydricalcohol selected from the group consisting of ethylene glycol,diethylene glycol and propylene glycol, and an amino compound selectedfrom the group consisting of ethanolamine, 3-amino propanol,decamethylene diarnine, and IO-aminodecanol.

11. A molded article having a composition comprising a resinouscellulose ester of a lower aliphatic monocarboxylic acid plasticizedwith from 15 to 25% based on the weight of said cellulose ester of aplasticizer comprising a diisocyanate-modified polyester amide, saiddiisocyanate being selected from the group consisting of hexamethylenediisocyanate, ethylene diisocyante, trimethylene diisocyanate,m-phenylene diisocyanate and cyclohexylene diisocyanate, and saidpolyester amide being a reaction product of asaturated dicarboxylic acidselected from the group consisting of adipic, succinic, sebacic andazelaic acids, a saturated dihydric alcohol selected from the groupconsisting of ethylene glycol, diethylene glycol and propylene glycol,and an amino compound selected from the group consisting ofethanolamine, 3-amino propanol, decamethylene diamine, andIO-aminodecanol.

12. A molded typewriter key resistant to staining by lipstick comprisingcellulose propionate plasticized with from 15 to 25% based on the weightof said cellulose propionate of a diisocyanate modified polyester amideand up to 7% based on the Weight of said cellulose propionate of amonomeric compound selected from the group consisting of butanedioldicaprylate, triethylene glycol dicaprylate, dibutyl sebacate, dioctyladipate and dioctyl phthalate, said diisocyanate being selected from thegroup consisting of hexamethylene diisocyanate, ethylene diisocyanate,trimethylene diisocyanate, m-phenylene diisocyanate and cyclohexylenediisocyanate, and said polyester amide being a reaction product of asaturated dicarboxylic acid selected from the group consisting ofadipic, succinic, sebacic and azelaic acids, a saturated dihydricalcohol selected from the group consisting of ethylene glycol,diethylene glycol and propylene glycol, and an amino compound selectedfrom the group consisting of ethanolamine, 3-amino propanol,decamethylene diamine, and IO-aminodecanol.

13. A molding composition for making molded products resistant tostaining by lipstick comprising a cellulose resinous organic ester of alower aliphatic monocarboxylic acid in particulate form plasticized withfrom 15 to 25% based on the weight of said cellulose ester of adiisocyanate-modified polyester amide, said diisocyanate being selectedfrom the group consisting of hexamethylene diisocyanate, ethylenediisocyanate, trimethylene disisocyanate, m-phenylene diisocyanate andcyclohexylene diisocyanate, and said polyester amide being a reactionproduct of a saturated dicarboxylic acid selected from the groupconsisting of adipic, succinic, sebacic and azelaic acids, a saturateddihydric alcohol selected from the group consisting of ethylene glycol,diethylene glycol and propylene glycol, and an amino compound selectedfrom the group consisting of ethanolamine, 3-amino propanol,decatnethylene diamine, and IO-aminodecanol.

References Cited in the file of this patent UNITED STATES PATENTS2,284,896 Hanford et al. June 2, 1942 2,333,639 Christ et al. Nov. 9,1943 2,333,922 Foster Nov. 9, 1943 2,523,999 Sattler et al. Sept. 26,1950

1. A COMPOSITION COMPRISING A RESINOUS ORGANIC ESTER OF CELLULOSE WITHAT LEAST ONE LOWER ALIPHATIC MONOCARBOXYLIC ACID PLASTICIZED WITH FROM15 TO 25% BASED ON THE WEIGHT OF SAID CELLULOSE ESTER OF A PLASTICIZERCOMPRISING A DIISOCYANATE MODIFIED POLYESTER AMIDE, SAID DIISOCYANATEBEING SELECTED FROM THE GROUP CONSISTING OF HEXAMETHYLENE DIISCYANATEETHYLENE DIISOCYANATE TRIMETHYLENE DIISOCYANATE, M-PHENYLENEDIISOCYANATE AND CYCLOHEXYLENE DIISOCYANATE, AND SAID POLYESTER AMIDEBEING A REACTION PRODUCT OF A SATURATED DICARBOXYLIC ACID SELECTED FROMTHE GROUP CONSISTING OF ADIPIC, SUCCINIC, SEBACIC AND AZELAIC ACIDS, ASATURATED DIHYDRIC ALCOHOL SELECTRD FROM THE GROUP CONSISTING OFETHYLENE GLYCOL, DIETHYLENE GLYCOL AND PROPLENE GLYCOL, AND AN AMINOCOMPOUND SELECTED FROM THE GROUP CONSISTING OF ETHANOLAMINE, 3-AMINOPROPANOL, DECAMETHYLENE DIAMINE, AND 10-AMINODECANOL.